diff --git a/gst-libs/gst/audio/audio-buffer.c b/gst-libs/gst/audio/audio-buffer.c
index e0165728d2..7d139f0b22 100644
--- a/gst-libs/gst/audio/audio-buffer.c
+++ b/gst-libs/gst/audio/audio-buffer.c
@@ -55,7 +55,7 @@ gst_audio_buffer_unmap (GstAudioBuffer * buffer)
 
 /**
  * gst_audio_buffer_map:
- * @buffer: pointer to a #GstAudioBuffer
+ * @buffer: (out caller-allocates): pointer to a #GstAudioBuffer
  * @info: the audio properties of the buffer
  * @gstbuffer: (transfer none): the #GstBuffer to be mapped
  * @flags: the access mode for the memory